A. Field of the Invention
The present invention relates generally to optical fiber systems and, more particularly, to systems and methods that detect an imperfect connection of fibers of an optical pump.
B. Description of Related Art
Optical communication systems have replaced other communication mediums due to their many advantages. For example, optical communication systems typically have wide bandwidth and low attenuation, are immune to electrical noise, offer relatively secure transmission of signals, and can transmit signals over long distances.
Despite the low attenuation of optical communication systems, the optical signals they transmit nevertheless require amplification. Although many types of optical amplifiers currently exist, the most widely used amplifier includes an optical fiber doped with an optically active material, such as erbium or other rare earth elements. Generally, the core region of the optical fiber contains the dopant, which is optically excited to provide optical gain to an optical signal having a suitable wavelength. The dopant may be excited by subjecting it to an optical pump signal of a suitable pump wavelength. For example, an erbium-doped fiber amplifier amplifies optical signals of wavelengths in the range of 1520 nm to 1580 nm when pumped by an optical pump signal of wavelength 980 nm or 1480 nm.
Conventional systems typically use optical pump lasers to generate the pump signal. The lasers generate optical pump signals of high power density in the pump fibers and the connectors. Imperfect connections, caused, for example, by imperfect mating of fibers or by surface contamination on the fiber ends, such as oils, dust, or dirt, can absorb some of the optical pump power and cause a hot spot, which could irreparably damage the connector. Once damaged, the connector must be replaced.
Accordingly, there exists a need for a system which detects an imperfect connection before damage occurs to the connector.